Humans have applied scents and fragrances to their skin since antiquity. Originally these aesthetically pleasing materials were commonly isolated in raw form as resins, gums or essential oils from natural sources, inter alia, the bark, roots, leaves and fruit of indigenous plants. These resins, gums, and oils were directly applied to the body or diluted with water or other solvent, including in some cases, wine. With the advent of modern chemistry, individual components responsible for the odor properties of these resins, gums and oils were isolated and subsequently characterized. However, formulators continue to search for materials which when applied to human skin or substrates and surfaces used by humans, will provide a pleasurable odor or scent and sustain that odor or scent for a long period of time.
With regard to laundry detergent compositions, in addition to the removal of stains, dirt, soil, grime, and grease from fabric, formulators have attempted to deliver a "fresh" or "clean" odor to washed clothing to provide an olfactory aesthetic benefit and to serve as a signal that the product is effective. Laundry compositions, including rinse-added fabric softeners and dryer-added substrates, are currently formulated with perfume and fragrance ingredients which are aesthetically pleasing to the consumer but which fail to deliver a prolonged "fragrance" or "pleasurable smell" to the finished, cleaned fabric.
It is well known that mixtures of perfume or fragrance raw materials when deposited on a substrate such as skin or fabric lose intensity and may change character with time, mainly due to factors such as differential evaporation and substrate penetration. Many attempts have been made to minimize these drawbacks, but so far without notable success. Particularly, efforts have been made to prolong the diffusion, as well as to improve other characteristics of fragrance materials, by e.g. increasing the fragrance raw material concentration or by using additives such as silicones, glycerol, polyethylene glycols and so on. Such additions, however, have never been adequate to increase the longevity of the fragrance odor.
Accordingly, there remains a need in the art for pro-fragrances compounds which can be formulated into personal use articles, laundry detergent and hard surface cleaning compositions wherein the "perfume character" is released in a manner which provides for fragrance longevity.